Tool to determine the proper angles of the cutting lips of twist drills



IN VEN TOR.

THE

Feb. 20, 1951 s. M. GooDRlcH TooL To DETERMINE THE PROPER ANGLES 0E CUTTING LIPS 0E TwTsT DRILLS Filed March 5, 194s @a EE@ Patented Feb. 20, 1,9:51

TOOL TO DETERMINE THE PROPER ANGLES OF THE CUTTING LIPS OF TWIST DRILLS Savy Max Goodrich, Lansing, Mich.

` Application March 5, 1948, Serial No. 13,264

1 Claim. I 1

This invention relates to tools useful in grinding the lips of twist drills, is particularly concerned with a tool for determining the angles of the cutting lips of twist drills, and is more particularly concerned with a modied form of the tool disclosed and claimed in my copending application, Serial No. 764,618, filed July 30, 1947, now Patent Number 2,506,868, issued May 9, 1950.

In the use of twist drills particularly for boring holes in metals it is very important that` the two cutting lips of the drill have the proper angle in respect to the axis of the said drill. Obviously, the angle of the cutting lip determines the length of the same, and it is for this reason that the angles of each of the two cutting lips be the same. Should the angle of the cutting lips vary the hole formed by the drill will be ofgreater diameter than the diameter of the saiddrill. It is therefore very important that the two lips of the cutting edge of a twist drill have the same angle and therefore be of the` same length.

In the past resort has been made to the use of graduated scales for determining the angle and length of the cutting lips of a twist drill. There are serious objections to the-use Aof such tools because each lip must be measured individually, and this is time consuming and such practice is at best substantially inaccurate.

It is an object of this invention to provide a tool by the use of which the angles of the lips of the drill can be determined rapidly. It is a further object to provide a tool whereby the angles of such lips canbe determined substantially accurately. It is a further object to provide a tool whereby the angles of the lips of twist drills may be determined by a worker who possesses only a limited amount of Amechanical skill.

I have now discovered and invented a tool for gauging twist drills comprising an adjustable V- rest for receiving the shank of a drill, a supporting rod, a base for supporting the said rod, a metal case, the said base being securelyattached to the top of the said case, 'anfindexing plate having a plurality of holes of varying dimensions, a vertical cylindrical shaft, the said plate being securely mounted on the top of the said vertical shaft, the said shaft extending downwardly through a cam, the said cam having a plurality of notches along a helical surface on the top of the said cam, an indexing finger attached to the said cylindrical shaft, the said indexing nger adapted to enter selectively each of the said notches, the said cam being securely attached to a horizontal plate fastened in the bottom of the said case, a pair of measuring scales, a pair of pointers, each of the said pointers being mounted on a fulcrum, each of the said pointers having a forked end, a pair of levers, the said forked end being received by a perpendicular pin at one end of each of the said levers, each of the said levers extending substantially from each of the said perpendicular pins, and each of the said levers being movably attached to a shaft, each of the said shafts being received in a bearing, one of the said levers extending to a short bar contacting the helical crest of the said drill, and the other said lever extending to a short bar contacting the cutting edge of the said drill, and the said tool adapted to indicate the length of the lips, and the angle of the said lips of twist drills, and I am now able to avoid the disadvantages of the rior art and am able readily to accomplish the objects set forth.

Referring to the drawings:

Fig. l is a plan view of my invention.

Fig. 2 is a side elevation of the same.

The metal case I has a handhole plate 2 attached to the side of the case by a plurality of screws 2a. Attached to the top of the said case is a base 3. The said base 3 is attached to the said case I by means of four screws 3a. The supporting rod 4 is held in a hole in the said base 3 and is further held by the adjusting screw 4a. The bearing piece 5 has a vertical hole through which the rod 4 is inserted. The said bearing piece 5 is adjusted and held in place by means of the set screw 5a. The steady rest B is inserted through a horffontal hole through the said bearing piece 5 and is adjusted and held in place by means of the screw l. A horizontal suppporting plate 8 is welded in the lower portion of the inside of the case I. A notched indexing cam 9 is welded to the said support plate 8. A pair of bearings Ill, and I I, support the vertical shaft I2. The bearing I3 is attached to the top of the case I; andthe bearing II is attached to the horizontal supporting plate 8. An indexing iiriger I3 is attached tothe shaft I2. An indexing plate I 4 is attached to the top of the shaft I2. The said plate I4 has a plurality of holes, I5 through 2liAl varying in diameter size to receive the cone proper of the various common sized drills. The supporting shaft 29 is supported bv a pair of bearings 2l, and 28. The said bearings 27, and 28, are attached to the inside of the t0n of the metal case I. The shaft 29 supports the lever 33. The upper end of the said lever 33 has a short bar 4!) attached thereto. A pin 3d is attached 3 to the lower end of the said lever 33, and is perpendicular to the said lever 33. The pointer 36 has a forked end 35. The pin 34 receives the said forked end 35 of the pointer 36. The pointer 36 pivots on the fulcrurn pin 31. The bearings 42, and d3, receive the shaft 4i. The shaft 4I carries the lever de. To the lower end of lever 44 a pin 55 is attached perpendicularly to the same, and the said pin' receives the forked end 4690i" the pointer i. the shaft 32. rllhe shaft 32 is received by the bearings 3Q, and 3 I, which bearings are supported' by the supports 3m. The;A lower: endw of* the pointer il is visible through the fwindow='48, andi points to the measuring scale 49. A small beveled bar 56 is attached to the upper endof-"thelever ed. The shank of a small drill5l; forjexample;

is placed against the V-rest 6, the indexingplate it is rotated so that the appropriate hole* (l5 through 26) is directly beneath the said drill, and

the cutting endof the `said drilli is placediina- Y smallfhole'in the indexingplate Hi; rI-he-V-resty isadjusted by unscrewing the set screw Tandbymovingthe shankof thesaidvfrestleither way through'the hole inthe bearing piece 5;y Whenl the V-rest isset in the properplace the set screw. 'i is scrcwedin against thejshankof the Saidv V- rest to keep it inplace; with the bar 5!) 'in contact with the cuttingV edges of the same. If the cuttingangles arev true-the pointer 4l will register cn'thirtysone'offthe scale 39. If 'the pointer; registers.A at either side ofthirtyeonath'e cutting edge'sneed to Ybereground. As the drill 5l .is1rotated,.the, helical crestV of the same'isin contactwith the bar` fill. If thecenter-V ing of the drill-is true the pointer 36 will register onthe zero markl ofthe scale 39.l If the pointer registers at either:A sideof the zero niark, thecenter is not true and the drill ne'eds to be rei-1 ground.

When a'drill'of a largersize', the,l drill 52 .for example, is to betested,` the indexplate' I4 is`ro tated andl depressed so that the-"indexing finger I3`V rests in the properl notch 53'V of the cam 9i lllv attached integrallyv t'o the upper.` end ofthe lever 33 is important in that it serves? in pre'- ventingthesaid end of thelever'frornfalling into The said pointery il pivots on The drill 5i, is rotatedY the helicalT grooveportion'of the' drill. As the v drill isv rotated andthe bar is inicontact with I wish fur-ther particularly to,` point out that theY beveled bar 50 attached'integrally to the upper-end of the lever 44. is-important in thatit serves in\ preventing the said` endy oftheV leverf from fallingf intothe helical groove portion oftheV drill.

As the drill is rotated andVthevvbar-is incontact. with` the helicall crest of one oftheA lips, thesaidbar extendsfsuiciently to comein contact with a portion of the other crest and thereby prevents the bar from falling into the helical groove.

I claim:

A tool'for gauging twist drills, comprising an adjustable V-rest for receiving the shank of a drill, a supporting rod on which the V-rest is adjustably mounted, a, base for supporting the said: rodi affmetalcase,` the! said` base being securely attached to* the topto'f' the'said"case, an indexing plate having a plurality of holes of varying dimensions, a vertical cylindrical shaft, the/.fsaidfplatefbeing; securely mounted on the top of thasaid-ivertiealshaft, a cam, the said shaft extendingw downwardly through said cam, there 'beigiaplrality of'notches along a helical surface: onthe; ton-fork the said cam, an indexing 1inger attached to the said cylindrical shaft, the said indexing nger adapted rto enter each of the said notches, a horizontal plate, the said cam being securely attached tot said i horizontal 'platee substantially-Marthe,bttomofthe-said case, a pair' of! m'eastir-ings ":aies"s.` al pair of pointers, each of the saidpointersbeirig'niounted on'a fulcrum, eac-li of thesaidfpointers having a forked end,

a pain oflevers, a-Lpair of pins', eachof the saidof eachfofi' thef'saidleversl; eachl ofl'thelsaid'levers moi/ablyv attached# to af-shaft, each of thev said UNi'rEn sfr-Aras ru=if11;.1\;r"1s

Numpefrff- Name: Date 60955951` -Mitche11" v w A ug. 30, 1899A 1,400,331 Y Turrettini" l.. Dec; 13, 1921 134319,61@7m Wittner; ont. 1o, 1922 11,487,092 Dir1ge1 v Mar. 18,1924 25391256 (renners- Nov.v 1o, 1942 2;324,'4{1e:y Beckerv .my 2o', 1943 2,377,715: pensent l- June 5, 1945 2 ,1385g396 Bamfv.- septl 25', 1945 2;506;86a- Goodrich- May 9, 1950 FOREIGNPATENTS Number Country Date z-iaefsaV yswitzeriarlaf; ll .Apr. 1,1942 876,955: Franca- 1-11 Nov. 19, 1942 OTHER REFERENCES gublication; American Machinist, May 22, 1930..k Y 

